Components of a turbine, such as turbine rotors and discs, are subjected to high stresses due to high operational speeds and temperatures. This results in the erosion of material in areas in which a turbine blade is attached to a disc (i.e. turbine blade attachment areas) and in shaft coupling areas, for example, that have complex geometries. In order to reconstruct or repair eroded areas of the turbine, a weld buildup process is used. In this process, an area to be repaired undergoes an initial machining step to prepare the area for welding. Weld material is then welded to the repair area to form a weld buildup that is subsequently heat-treated. A final machining step is then performed in order to form a desired machined shape from the weld buildup. Prior to final machining, an ultrasonic inspection is performed in order to detect flaws in the weld buildup and determine the size of the flaws.
The ultrasonic inspection is performed manually using a conventional ultrasonic straight beam probe. However, this type of arrangement can only detect flaws that are oriented in a horizontal direction (i.e. 0 degrees). Therefore, it is desirable to provide improved flaw detection techniques in a turbine component.